Cargo vehicles are available in a number of shapes and sizes. They are generally characterized by a cab and a cargo portion. The cargo portion has walls which form an enclosure. Cargo trailers are often referred to by their shapes, such as “cube” or “high cube.” A number of materials have been used in the trailer industry for constructing the walls of cargo trailers, but to Applicant's knowledge the prior art does not suggest the laminates of the present invention.
Particularly in the case of commercial cargo transport vehicles, it is important to minimize the weight of the vehicle to the extent possible. Due to the large surface area of the trailer walls, the walls contribute significantly to the overall weight of the vehicle. Many lightweight materials exist, but most cannot be used to form trailer walls due to a lack of strength. That is, in most instances it is important that trailer walls provide certain minimum structural characteristics, including resistance to punctures, adequate bending stiffness and strength and overall structural durability. While solid metal walls certainly provide the required attributes of stiffness and strength, inexpensive solid metal plates such as steel are heavy which reduces fuel efficiency and makes trailer manufacture more difficult. Moreover, lightweight exotic metals are simply too expensive to use in the construction of trailer walls.
One prior art trailer body construction is disclosed in U.S. Pat. No. 4,212,405, entitled ALUMINUM PANEL CONTAINER FOR A TRAILER BODY. Therein, a cargo-carrying container for a trailer body construction has sidewalls and inwalls consisting essentially of unitary aluminum alloy plates having a thickness of at least about {fraction (5/32)}″. In U.S. Pat. No. 4,685,721, entitled PLATE TRAILER, there is disclosed a trailer body in which each sidewall comprises at least two groups of flat rectilinear plates of lightweight metallic material such as aluminum alloy. The plates are lined in side-by-side relation and are joined by a plurality of joining panels situated on the exterior surface of the sidewall. Each group of plates has a uniform thickness, but the plates of a first of the at least two groups are appreciably thicker than the plates of the second of the at least two groups. It is stated therein that by positioning the group of thinner plates in the region of lower stress, the total weight of the trailer can be reduced, thereby enhancing the cargo weight capacity of the trailer while retaining the high freight cubic capacity desired.
In U.S. Pat. No. 4,940,279, entitled CARGO VEHICLE WALL CONSTRUCTION, a plate wall trailer is disclosed in which each sidewall and frontwall comprises a multiplicity of composite panels. Each composite panel comprises a laminated sandwich including a polypropylene core having a preferred thickness of 0.250″ and 0.040 inch aluminum face sheets adhesively attached to each surface of the polypropylene core, An epoxy adhesive having polypropylene particles dispersed therein is used to attach the aluminum face sheets to the polypropylene core. The preferred overall thickness of the disclosed composite panel is approximately 0.33″.
In co-pending U.S. patent application Ser. No. 08/947,030 filed Oct. 8, 1997, entitled STRUCTURAL PANEL WITH KRAFT PAPER CORE BETWEEN METAL SKINS, which has been assigned to the assignee of the present invention and the entire disclosure of which is incorporated herein by reference, there is disclosed a new laminated material in which thin metal skins are bonded to and separated by an intervening layer of paper.